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89 lines
2.5 KiB
89 lines
2.5 KiB
/* hwclock.c - get and set the hwclock
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*
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* Copyright 2014 Bilal Qureshi <bilal.jmi@gmail.com>
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*
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* No standard, but see Documentation/rtc.txt in the linux kernel source..
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*
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USE_HWCLOCK(NEWTOY(hwclock, ">0(fast)f(rtc):u(utc)l(localtime)t(systz)s(hctosys)r(show)w(systohc)[-ul][!rtsw]", TOYFLAG_SBIN))
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config HWCLOCK
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bool "hwclock"
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default y
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help
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usage: hwclock [-rswtluf]
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Get/set the hardware clock.
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-f FILE Use specified device file instead of /dev/rtc0 (--rtc)
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-l Hardware clock uses localtime (--localtime)
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-r Show hardware clock time (--show)
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-s Set system time from hardware clock (--hctosys)
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-t Set the system time based on the current timezone (--systz)
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-u Hardware clock uses UTC (--utc)
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-w Set hardware clock from system time (--systohc)
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*/
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#define FOR_hwclock
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#include "toys.h"
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#include <linux/rtc.h>
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GLOBALS(
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char *f;
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)
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void hwclock_main()
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{
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struct timezone tzone;
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struct timeval timeval;
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struct tm tm;
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int fd = -1, utc;
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if (FLAG(u)) utc = 1;
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else if (FLAG(l)) utc = 0;
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else utc = !readfile("/etc/adjtime", toybuf, sizeof(toybuf)) ||
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!!strstr(toybuf, "UTC");
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if (!FLAG(t)) {
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if (!TT.f) TT.f = "/dev/rtc0";
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fd = xopen(TT.f, O_WRONLY*FLAG(w));
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// Get current time in seconds from rtc device. todo: get subsecond time
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if (!FLAG(w)) {
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xioctl(fd, RTC_RD_TIME, &tm);
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timeval.tv_sec = xmktime(&tm, utc);
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timeval.tv_usec = 0; // todo: fixit
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}
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}
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if (FLAG(w) || FLAG(t)) {
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if (gettimeofday(&timeval, 0)) perror_exit("gettimeofday failed");
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if (!(utc ? gmtime_r : localtime_r)(&timeval.tv_sec, &tm))
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error_exit(utc ? "gmtime_r failed" : "localtime_r failed");
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}
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if (FLAG(w)) {
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/* The value of tm_isdst is positive if daylight saving time is in effect,
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* zero if it is not and negative if the information is not available.
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* todo: so why isn't this negative...? */
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tm.tm_isdst = 0;
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xioctl(fd, RTC_SET_TIME, &tm);
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} else if (FLAG(s)) {
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tzone.tz_minuteswest = timezone / 60 - 60 * daylight;
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} else if (FLAG(t)) {
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// Adjust seconds for timezone and daylight saving time
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// extern long timezone is defined in header sys/time.h
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tzone.tz_minuteswest = timezone / 60;
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if (tm.tm_isdst) tzone.tz_minuteswest -= 60;
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if (!utc) timeval.tv_sec += tzone.tz_minuteswest * 60;
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} else {
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strftime(toybuf, sizeof(toybuf), "%F %T%z", &tm);
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xputs(toybuf);
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}
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if (FLAG(t) || FLAG(s)) {
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tzone.tz_dsttime = 0;
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if (settimeofday(&timeval, &tzone)) perror_exit("settimeofday failed");
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}
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xclose(fd);
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}
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